If you wish to automatically back up files from one or more Windoze systems, the way to do it is definitely via rsync. Rsync uses a sophisticated checksum algorithm to only copy the actually changed portions of the files it copies so it works perfectly for maintaining backup copies. Furthermore, it can be set up to delete previously-copied files that are deleted from the source directory so that the backup directory becomes a true mirror of the source directory that it backs up.
An rsync client on the NAS4Free system requests copies of files from an rsync server on the Windoze system that is to be backed up. This being the case, the rsync server must be installed on each Windoze box. The easiest way to do this is get the latest copy of DeltaCopy from:
http://www.aboutmyip.com/AboutMyXApp/DeltaCopy.jsp
Download the "With Installer" version of DeltaCopy, unzip it and run the installer. Follow the instructions for each install step. You might want to change the install directory to "\Program Files\DeltaCopy" instead of the default directory (in the top-level of the directory tree).
Once you've installed DeltaCopy, you need to register the server as a service with Windoze. Registration will take place the first time you run the DeltaCopy server. It will cause Windoze to start up DeltaCopy when the system boots and ensure that the service stays up and running. Note that, when you register the service, you should check the log on as "Local System account" button and eschew supplying a username and password. This will allow the service to run as a system service (its a good thing).
Next, you should create aliases for all of the directories on each of the Windows systems that you want to back up. This is done by clicking on the "Virtual Directories" tab of the DeltaCopy Server Console. Under that tab, you can click on "<Add New Directory>" to add one or more directory aliases to be shared via rsync. Unfortunately, you can't include more than one directory under an rsync alias so you'll have to define as many aliases as the directories that you want to back up (making the top level directory an alias is not recommended). You should check the "Read only" box to ensure that rsync on the NAS4Free system does not monkey with any of the local files. You may want to delete the default "Backup" directory that appears automagically, when DeltaCopy is set up. It serves no purpose for us.
That's about it for Windoze. You can check that the rsync server is working, from the NAS4Free system, with this command:
/usr/local/bin/rsync rsync://mysys
Where "mysys" is the name of the system that is running the DeltaCopy server. You should see a list of modules (share points).